Moustafa was sentenced to death last May after being convicted of paying a retired Egyptian police officer, Mohsen el-Sukkary, $2m (£1.3m) to kill 30-year-old Suzanne Tamim, while she was in Dubai in July 2008. Sukkary will also be retried.

The case captivated Egyptians as it involved a member of an elite often viewed as above the law.

Moustafa, a 50-year-old businessman, is tied to President Hosni Mubarak's son Gamal and is an influential member of the ruling party. A member of parliament's upper house, the shura council, he was also a member the ruling party's policies committee, which the younger Mubarak chairs. The court decision to retry the case is certain to raise charges that Moustafa's influence will keep him from the gallows.

Tamim rose to stardom in the late 1990s, but hit troubled times, separating from her Lebanese husband-manager, who filed a series of lawsuits against her.

Tamim and Moustafa met in the summer of 2004 at a Red Sea resort, according to transcripts of Moustafa's interrogation that were widely published in Egyptian newspapers.

Sukkary said in the transcripts in the trial that Moustafa was "always with Tamim", that he kept a hotel suite for her, and that he took her around in his private jet.

During interrogations, Moustafa said he broke up with Tamim after his mother opposed the couple's marriage plan. Moustafa comes from a religiously conservative Muslim family.

According to Dubai investigators, Sukkary stalked Tamim to her apartment in the luxury Dubai Marina complex and entered using an ID of the management company from which she had recently bought her property.

Blood-soaked clothes were found dumped outside the building, and police say the killer's face was captured on security camera footage.

Sukkary was arrested in August 2008 in Egypt. Dubai police travelled to Cairo to present their evidence against him but then turned their attention to Moustafa.

Egypt declined to extradite Moustafa to the United Arab Emirates, insisting he be tried at home. That move was initially read by many Egyptians as opening the door for a slap on the wrist for Moustafa, who built a real estate empire of luxury hotels and resorts and was a leading force behind the expensive western-style suburbs that ring Cairo.